The field of the invention is in the biomedical human environment art.
The use of pressurized suits in low pressure and in high gravitational force environments to protect the human body is well known. The conventional prior art means for controlling the pressure in a pressure suit has been with a conventional anti-G valve, such as an Alar type MS24350-1, schematically illustrated in FIG. 1. As illustrated in FIG. 2, the conventional pressurizing system using a conventional valve has only one inflation schedule. When the conventional valve having lower body 11 and upper spring chamber 19 is oriented as shown an increase in +G.sub.Z force 12 will cause the mass 13 to descend, so that the rubber seat 14 will cover and depress the pilot port 15 and provide for air to flow from the inlet port 16 to the outlet port 17 until the pressure at the outlet port 17 balances the pressure of the mass 13 that is being acted upon by the gravitation force 12. Thus, the pressure in an anti-G garment is substantially proportional to +G.sub.Z. When the acceleration decreases, the valve action reverses and allows excess pressure to escape. FIG. 2 illustrates graphically an inflation schedule 21 of a typical anti-G valve such as the type MS24350-1. It may be noted that normally it doesn't come on, that is the rubber seat 14 is not moved down into contact with port 15, until a +G force of approximately 2.2 acts on mass 13 sufficiently compressing spring 18. This is shown at point 22 on curve 21 of FIG. 2. The rate of air pressure into the pressure garment per unit of G force is approximately 1.5 pound per square inch per gravitational unit after turn on. This is commonly referred to as the ramp characteristic of the valve.
The best known prior art is that contained by the following patents. U.S. Pat. No. 2,509,295 to patentee Glass; U.S. Pat. No. 2,812,481 to patentee Roosdorp; and U.S. Pat. No. 3,586,027 to patentees Fitzgerald, Jr., et al.